The present invention relates to a method of plasma enhanced chemical vapor deposition (C.V.D.) of a phosphosilicate glass (P.S.G.) film on a substrate and, more specifically, it relates to a method of plasma enhanced C.V.D of a phosphosilicate glass film on a substrate such as a silicon substrate or an aluminum wire pattern on a silicon substrate.
As is known in the art, a phosphosilicate glass film is used as a protective coating (or a cover film) or an interlaminar insulation film for wire pattern layers. Conventional chemical deposition methods for depositing these films on substrates are mainly classified as a so-called "atmospheric pressure method" and a so-called "low pressure method". In the atmospheric pressure method, a phosphosilicate glass film is deposited on a substrate from a reaction gas mixture including SiH.sub.4, PH.sub.3 and O.sub.2 under atmospheric pressure (i.e. 760 Torr) and at a temperature of from 350.degree. to 450.degree. C. On the other hand, in the low pressure method, a phosphosilicate glass film is deposited on a substrate from a reaction gas mixture including SiH.sub.4, PH.sub.3 and O.sub.2 under a low pressure (e.g. 1 Torr) and at a temperature of from 350.degree. to 450.degree. C.
Furthermore, with regard to the deposition of a nitride film or amorphous silicon, a so-called "plasma enhanced (or assisted) chemical vapor deposition method" is proposed. According to this method, a silicon nitride film or amorphous silicon film is deposited at a relatively low temperature (e.g. 20.degree.-450.degree. C.) by applying a radio frequency signal between parallel flat plate electrodes to generate plasma gas (e.g. see Electrochemical Society Meeting "Extended Abstract" 79-1, 262(1979) and Journal of Electrochemical Society 125, 601(1978)).
However, there are problems in the phosphosilicate glass films obtained from the above-mentioned conventional chemical vapor deposition methods in that, in the case where the deposited phosphosilicate glass films are heat-treated, even at a temperature of about 600.degree. C., cracks are likely to be generated in the deposited films. In addition, in the case where the deposited phosphosilicate glass films are cooled to room temperature after the deposition, the deposited phosphosilicate glass film is strained, whereby cracks are likely to be generated in the deposited films.